Functional Ovarian Cysts
Follicle and Corpus Luteum Cysts

follicle and corpus luteum


Functional Ovarian Cysts


What Are Functional Ovarian Cysts?
What Are The Types?
What Are The Symptoms?
What Causes Them?
How Are They Diagnosed?
How Are They Treated?

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Guide To Ovarian Cysts

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What Are Functional Ovarian Cysts?

Functional cysts are small fluid filled blisters which develop in or on the ovaries during a woman's menstrual cycle. In most cases they remain harmlessly undiagnosed and disappear within a few weeks. It is estimated that nearly 7 percent of women are affected by functional cysts and they are only usually discovered during a routine pelvic exam. Treatment of functional ovarian cysts is only necessary if symptoms occur, such as pelvic pain or heavy periods (menorrhagia). Occasionally cysts do not clear up and can grow to the size of an orange (or larger) causing severe pain, particularly if they become twisted, bleed or burst. Ovarian cysts during pregnancy, if they occur, are most likely to form in the second trimester, when hCG (the 'pregnant hormone') levels peak.

What Are The Types?

Functional cysts are closely related to the menstruation cycle and generally are asymptomatic (no symptoms) so do not require treatment. There are 2 types of functional cysts: follicle and corpus luteum.

Follicle Cysts

During a normal menstrual cycle a woman's ovaries produce an egg. The egg grows inside a sac called a follicle. When the egg is released (ovulation) it travels down the fallopian tube on its journey to the uterus (womb) for implantation. If the egg does not become fertilized along the way, implantation does not occur and the lining of the uterus breaks down and is expelled during a menstrual bleed. However, where ovulation does not occur and the egg is not released, a follicle cyst occurs (image). This can swell and continue to grow up to 6cm in diameter.

Corpus Luteum Cysts

Corpus luteum cysts (image) are another type of functional cyst. In this instance ovulation does occur and the egg is released. After this happens the follicle sac does not dissolve (as it should) and instead becomes known as a corpus luteum. The sac seals off and fluid, and sometimes blood, builds up inside. Usually this type of cyst only occurs on one ovary and produces no symptoms. If there is pain, it is only on one side of the pelvic area. However in some circumstances the cysts can grow to almost 10cm in diameter.

What Are The Symptoms?

In the majority of cases, functional cysts cause no symptoms and normally clear of their own accord within a few weeks or months. Where symptoms do occur it is generally more related to the size and location of the cyst.

• Follicular cysts can cause excess estrogen production, leading to metrorrhagia (uterine bleeding or spotting between periods) and menorrhagia (heavy periods). See also, can ovarian cysts cause a missed period?

• Most symptomatic ovarian cysts produce a dull vague pelvic pain and women complain of a feeling of 'heaviness'. See also, what type of pain do ovarian cysts cause?

• Some women experience tenesmus, a termed used to describe straining during a bowel movement or urination.

Dyspareunia/pain during sexual intercourse may also occur, as well as bloating or swelling of the tummy, abdomen. For more detail and personal stories see, what are the signs of ovarian cysts?

Cyst Complications

Occasionally if a cyst becomes larger than 10cm it develops complications, although large cysts are more associated with uterine fibroids, endometriosis implants and polycystic ovarian syndrome. When a cyst becomes enlarged it may become twisted resulting in spasmodic pain. Where a cyst ruptures (bursts) the woman is likely to feel a sudden sharp pelvic pain. This may be induced by exercise, sexual intercourse or trauma. Occasionally when pain occurs in the middle of the menstrual cycle (during ovulation) this is known as mittelschmerz. If pain is accompanied by nausea or vomiting, see your doctor immediately as this may indicate hemorrhage. Read also, what causes ovarian cysts to rupture?

What Causes Them?

Why cysts occur or develop is not really known yet, but chances are several factors are at play. What we do know is that hormone production and levels are probably a key component. Additionally, scientists have identified a number of factors which appear to increase a woman's risk of developing ovarian cysts. These are:

• Pregnancy, functional cysts are relatively common in the second trimester of pregnancy.
• Multiple pregnancies (twins, triplets etc) increase the risks.
Ovarian stimulation with fertility drugs.
• Gestational trophoblastic disease (GTD), a rare tumor which grows in the uterus of women of reproductive age.
Hypothyroidism may stimulate cyst growth.
• Risks are increased with cigarette smoking.
• Mirena coils: Does the coil increase the risk of ovarian cysts?

How Are They Diagnosed?

The majority of women with functional cysts probably remain undiagnosed. Where diagnosis does occur it is usually by accident during a routine pelvic exam or by ultrasound performed for other reasons. Further diagnostic tests are only usually performed where the woman is experiencing painful symptoms, irregular periods or infertility issues. If cysts have developed to a reasonable size the doctor may be able to feel them during a pelvic exam. After this possible tests include:

Ultrasound: An ultrasound scan and/or other imaging tests including CT Scan, MRI scan and doppler flow study.

Blood Tests: CA125 may be ordered to test for ovarian cancer (more important for women after menopause or who were returned an abnormal ultrasound scan).

Hormone Levels: LH, FSH (follicle stimulating hormone), estrogen and progesterone levels can be tested as well a serum HCG (see an explanation for these hormones at: pregnancy test).

How Are They Treated?

Birth Control Pill

Functional ovarian cysts do not usually need treatment as they often disappear within 12 weeks. However, where they do persist, an oral contraceptive is routinely prescribed (unless pregnancy is desired). Decades ago researchers discovered that women on 'the pill' had far fewer cysts than those who were not. Since then, women with cysts have been prescribed birth control pills to make them disappear faster. One recent study however throws doubt on this opinion and claimed that oral contraceptives did nothing to speed up the disappearance of cysts. For natural therapies, read natural treatment for ovarian cysts.


Surgery is uncommon for the treatment of functional cysts and is only usually discussed as an option where:

• Cysts and symptoms persist.
• Cysts are larger than 5 cm.
• Cysts appear in women who are in or nearing menopause (as there is an increased danger of cysts becoming cancerous after menopause).

The types of surgery for functional cysts include exploratory laparotomy and cystectomy. Functional cysts in women who are still having periods have a high chance of disappearing on their own accord. See also, do ovarian cysts usually need to be surgically removed?

Other Types: See Dermoid Cysts.

  Related Articles on Cysts

For more gynecological issues, see the following:

Can ovarian cysts cause infertility?
Symptoms of ovarian cysts: Common and less common signs.
Treatment for ovarian cysts: Overview of therapies.
What is the difference between ovarian cysts and PCOS?

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